Just because the gifts are opened and the paper is strewn about the living room, it doesn't mean the fun of Christmas is over. Add some fun party games to Christmas day to extend the fun of Christmas!
If you have a large gathering on Christmas day, have fun with the hat game. When they arrive, give everyone a Santa hat. These are inexpensive and can be purchased for $1 at the dollar store, or even less in bulk, if you plan ahead. As everyone goes about their business of getting food, chatting with others and the like, the room will look very festive with everyone wearing their Santa hats.
However, the object of this game is to not have your hat on. As people forget about the hats, the object is to get rid of your hat and not be the last one wearing a Santa hat. Inevitably, there will be one person so wrapped up in a conversation or the buffet table, they forget to take off their hat and will be left the game's loser. This is a game that can be played again and again as you head forward with the day's festivities.
One fun memory game that kids particularly like is to make everyone pay careful attention to all the gifts that are opened on Christmas day. After the gifts are removed from the room (or you remove yourselves from the gift room) have everyone try and remember every single gift everyone got. Include stockings and any food gifts. Tell people they only have to remember the items that were opened that day, not any gifts they received and opened prior to Christmas day. This can be a fun game that's particularly popular with kids because they love to relive the gift magic. In addition, if they were so immersed with their own gifts they didn't notice anyone else's this is a good chance for them to educate themselves about what everyone got that day.
If you need a game to keep everyone busy before dinner, try the "guess me" game. Buy some large heavy socks, not low-rise, but the type that are worn outdoors in the winter that are thick and come at least to the calf. Put several items in the socks. Make sure identical items are in each sock. These items should be related to Christmas in some way. You might include a small ornament, scotch tape, a pinecone, a Hershey's kiss, and the like. Have each person feel the socks (having two socks just makes the game go faster, but you can play with just one sock), and write down their guesses about what's in the socks. Be sure to tell everyone how many items are in each sock. The winner gets, you guessed it, one of the socks!
If you have a bunch of wanna-be performers in your group on Christmas day, how about playing a little game of "Christmas Idol"? Set up a small table for the "judges" and have teams of 2 people (or individuals, if they want) sing a Christmas carol. Tell them to have a lot of fun with the song, and even add a Santa hat or other dress-up items if they wish. The winners can take home a CD of Christmas music. This game is particularly fun if just the children want to perform and be judged by the adults, or if, conversely, the adults perform and are judged by the children.